Proposed studies will employ laboratory experimental methodologies of frequent contact and objective measurement to study experimental alteration of smoking with interventions derived from smoking cessation treatment. Studies will employ behavioral motivational contingent reinforcement techniques to generate daytime smoking reduction and smoking abstinence in regular cigarette smoker volunteers. Expired air carbon monoxide levels will be used to assess smoking rates and reinforce reductions in smoking. Initial studies will vary target carbon monoxide levels and monetary incentive values in order to determine the functional relationships between smoking and parameters of contingent reinforcement. Optimal parameters for achieving daytime smoking reduction will then be selected and used in an "abstinence test" which will provide an index of treatment efficacy for evaluating specific components of smoking cessation treatment in a treatment analogue situation. The first treatment analogue study will determine whether improvements in abstinence rates result when gradual reduction precedes attempts at smoking abstinence. A subsequent study will compare contingent reinforcement and stimulus control techniques for their efficacy in promoting smoking reduction and subsequent smoking abstinence. Information obtained in these studies will be useful for developing effective smoking cessation treatment programs and evaluating components of existing treatment programs.